The overall objective of this proposal is the study of human visual functioning, both retinal and cortical, by means of the ERG and the evoked cortical response (VER). Both basic experimental and clinical research studies are proposed. One project is to investigate the effect of colored stimuli on VER source localization. From potential contour mapping and theoretical considerations of spread of current in volume conductors, it is proposed to conduct further studies on the origins of the early components of the visual evoked response in secondary or primary visual cortex. With the aid of an electronic alpha rhythm scorer, quantitative studies will be made on alpha interference with the VER, and on Lippold's theory of alpha rhythm origin. Macular electroretinograms will be stimulated with alterating pattern stimuli, and spectral sensitivity of patients with cone degenerations will be studied to learn more about retinal cone diseases.